A pressure-sensitive resistance element the electric resistance of which reduces gradually or linearly in proportion to an applied pressure has been used for various uses as a pressure sensor. The materials showing the above-described characteristics include a pressure-sensitive electrically conductive elastic body (elastomer) composed of a high molecular elastic body such as silicone rubber compounded with electrically conductive particles. For example, JP-A-53-79937 and 54-80350 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") describe that a rubber sheet which is composed of a high molecular elastic body compounded with conglomerated artificial graphite has pressure sensor like characteristics. Also, JP-A-56-108279 describes that a pressure-sensitive resistance element composed of two electrode plates having sandwiched therebetween a pressure-sensitive resistance layer composed of a binder resin (e.g., an acrylic resin) compounded with a molybdenum sulfide powder will change in resistance thereof in inverse proportion to a pressure being applied.
However, these conventional techniques have such disadvantages that in the former case, the applied pressure range capable of giving a pressure sensor like resistance change is narrow and, in the latter case, the changing range of the resistance is narrow.
That is, in the former case the applied pressure range capable of giving a pressure sensor like resistance change is considerably narrow as from about 30 g to about 1 kg only ,and the change of the resistance is rather narrow as from 10 k.OMEGA. to several hundreds .OMEGA.. Also, in the letter case, the element shows pressure sensor like characteristics in a relatively wide pressure range of from 30 g to 8 kg but the change of the resistance is extremely narrow as from about 10 k.OMEGA. to 3 k.OMEGA..